GEO-SPATIAL MAPPING OF IRON (FE) AND MANGANESE (MN) PRESENT IN GROUNDWATER OF CLARK, PHILIPPINES

Abstract

The study covers a comprehensive analysis of Fe and Mn to characterize their distribution and occurrence within the Clark Freeport Zone. 3-year groundwater samples taken from 39 wells/boreholes scattered throughout the study area. Fe was most frequently detected with concentrations near the limits of Philippine National Standards for Drinking Water (PNSDW).  0.42% of the 958 studied samples for Fe had concentration greater than the 1mg/L limit.  As for Mn, none of the 909 samples for Mn had concentration greater than the PNSDW. Of those wells that have shown presence higher than the minimum detection level (MDL), 5 have been installed with individual filtration system (DMI-65) to capture Fe and Mn. No correlation has been found between the two parameters. As for seasonality, there is an obvious spike in Fe for all wells during the months of July, September, and October. Mn on the other hand manifested a spike in July for the shallow wells. The QGIS3 software was also used to develop a spatial map and report the distribution presence. From the generated maps, Fe and Mn gradually increase in concentration going north to northeastern directions of CFZ. The produced map can be key in raising awareness of the public and fellow water concessionaires with regards to the possible extent of underground Fe and Mn presence. Information generated here will be valuable as resources, and engineering controls can be applied to give priority to the low probability affected areas.